You know what’s the scariest thing about skyrocketing college tuition?

We don’t know the cause.

That’s right. Tuition keeps spiraling, yet experts can’t pinpoint the reasons. Often there’s less solid analysis than political ballyhoo, which is pretty much the status quo for any facet of American life these days.

And sure, everything costs more, eventually. But not like college tuition.

In 2012, Atlantic Monthly took a look at the matter. To seek perspective, it compared tuition to the housing bubble. From 1999 to 2008, housing-related debt increased threefold. However, during the same period, student loans rose twice that.

Mind you, that period ended in 2008, when the national student-loan debt was just over $600 billion. It’s now over $1 trillion. How much is a trillion? It’s hard to fathom figures like that, but it’s a heck of a lot of money that can’t otherwise fuel the economy.

I went to a state school to get a bachelor’s degree. In 1987, the year after I graduated, tuition and fees were about mid-range for Illinois four-year universities: $1,630. By last academic year, that sum had zoomed to $9,096, an increase of more than 450 percent.

If you were to apply the same hike elsewhere, minimum wage would be almost $19, stamps would cost $1.23, gasoline would run $5.30 a gallon, a dozen eggs would sell for $4.35 and a gallon of milk would set you back $12.72.

So, why has tuition gone bonkers? That’s where debate comes in. Some sources point to increases in university research. Others point to higher costs in teaching (though, as a part-time college instructor, I can say that my pay has had almost no part in increased costs).

But the biggest wrangling focuses on government loans and state spending. One thought holds that as government loans have become easier to obtain, schools have boosted their tuition simply because they can.

Others say more loans are needed because states don’t fund colleges as much these days. According to the financial news site zerohedge.com, state spending has gone down in 48 states since 2008, topped by a 48 percent decline in Arizona. Illinois is 10th lowest among states, cutting funding 13.5 percent.

Regardless of where to foist blame, we still have the lingering question: what’s the problem? Again, the answer comes with debate.

Page 2 of 2 - On one side, there is great worry about saddling students with too much debt to the point they spend much of their lives and income trying to break even. A recent piece in the Huffington Post urged civil disobediece to push for reform.

But the other side says the hue and cry is simply an effort to let borrowers off easy with debt relief. Some point to a Brookings Institution study earlier this year, which found that debt horror stories are relatively uncommon. Only 7 percent of young-adult households have $50,000 or more in student loans. In fact, 58 percent of such households have less than $10,000 in debt.

Is all this debt worth the trouble? Yes, according to a study this year by the Federal Reserve Bank of San Francisco. The findings showed that an average college grad paying $20,000 per tuition year will recoup those costs by age 40 or sooner. Further, that grad will earn $800,000 more by retirement than the average high-school graduate.

Still, the study points out a massive risk: not finishing school. Among households with some college but no bachelor’s degree, loan debt has more than doubled over the past 20 years.

So what does all of this debt mean to the economy? Atlantic’s best guess: “This student loan growth sure looks unsustainable. But it’s hard to see how this bubble’s inevitable pop might look. Ultimately, it might look more like a balloon slowly deflating, if a large portion of college graduates decide to strategically default on their debt over time.”

That doesn’t sound good. You usually can’t use bankruptcy to erase student loans. So, “strategically” defaulting might mean simply being unable to pay.

It all sounds frightening for America’s economic stability. In a few years, let’s hope the lesson we learn about student loans isn’t as painful as the lesson from the mortgage collapse.